Inflammation or pain during early neonatal development results in long-term structural and functional alterations in nociceptive processing. While this phenomenon has been extensively studied within the somatosensory system, the impact of neonatal inflammation on the viscerosensory system is relatively unknown. This proposal has been designed to address the long-term effects of neonatal colon inflammation on the processing of visceral pain in adult mice. A model of neonatal colonic inflammation in mice will be used to determine if permanent changes can be induced in anatomical and physiological properties of visceral afferents, causing them to become permanently sensitized and thereby establishing a state of chronic visceral hyperalgesia. Using a combination of anatomical and physiological techniques, changes will be investigated in 1) the central and peripheral termination patterns and spinal organization of colonic afferents, 2) nocifensive responses to noxious stimuli and 3) the electrophysiological response patterns of colonic afferents. The data obtained here will provide important information regarding the plasticity of the viscerosensory system during neonatal periods.